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Thread: Blackhole Dark Energy

  1. #1 Blackhole Dark Energy 
    Senior Member MaxPayne's Avatar
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    This is my first question

    Is matter getting converted into dark energy inside black holes?
    What can we say about dark energy?Is it uniform everywhere or is it like ripples that are produced at some points in space and are spreading.
    I think we are using red shift and apparent brightness to measure the distance of galaxies from us.But this can only be accurate if dark energy is increasing at the same rate everywhere in space.What do you guys, think?
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  2. #2  
    Senior Member Strange's Avatar
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    Quote Originally Posted by MaxPayne View Post
    Is matter getting converted into dark energy inside black holes?
    Almost certainly not. By definition, nothing that happens inside a black hole can affect the rest of the universe.

    What can we say about dark energy?
    Not much, I don't think. Just that it has an apparent repulsive effect.

    Is it uniform everywhere
    Seems to be.

    I think we are using red shift and apparent brightness to measure the distance of galaxies from us.But this can only be accurate if dark energy is increasing at the same rate everywhere in space.
    Cosmological red shift has no (direct) relation to dark energy, just the expansion of the universe. Dark energy is hypothesized to explain the apparent increase in the rate of expansion at some point in the past.

    We observed red-shift before dark energy was known to be necessary.
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  3. #3  
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    Almost certainly not. By definition, nothing that happens inside a black hole can affect the rest of the universe.
    Under the assumption that blackhole is real singularity right?Photon can't escape a blackhole,but what about energy in some other more degenerate form,like dark energy?
    What is energy in it's true form?Can gravity affect non particle form of energy?

    Not much, I don't think. Just that it has an apparent repulsive effect.
    Is it repulsive...or can it be just dispersing like waves through space,like any other form of energy?,stretching and re arranging it.

    I am assuming that dark energy isn't uniform across the space and that it is formed around black holes; dispersing throughout space like waves, expanding space along with it.

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  4. #4  
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    Quote Originally Posted by MaxPayne View Post
    Under the assumption that blackhole is real singularity right?
    Actually, under the assumption that a black hole has an event horizon. (The existence or otherwise of a singularity is irrelevant.)

    Photon can't escape a blackhole,but what about energy in some other more degenerate form,like dark energy?
    Nothing, no energy nor information, can leave the black hole.

    Can gravity affect non particle form of energy?
    I'm not sure what a "non particle form of energy" is. But all energy has a gravitational effect (and is affected by gravity).

    Is it repulsive...
    Well, more accurately, negative pressure, I think. But yes, it does, by definition. That is why it causes acceleration of expansion.

    or can it be just dispersing like waves through space,like any other form of energy?,stretching and re arranging it.

    I am assuming that dark energy isn't uniform across the space and that it is formed around black holes; dispersing throughout space like waves, expanding space along with it.
    Then you will need to show the math that demonstrates that that can produce the observed acceleration.
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  5. #5  
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    Quote Originally Posted by MaxPayne View Post
    Can gravity affect non particle form of energy?
    Yes, all forms of energy interact with gravity; this goes for mass, but also for things like electromagnetic fields, strains and stresses etc etc.

    I am assuming that dark energy isn't uniform across the space
    You assume wrongly. Dark energy is constant everywhere in space ( unlike dark matter ), which is why it can be associated with the cosmological constant in Einstein's field equations.
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  6. #6  
    Senior Member MaxPayne's Avatar
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    @hi, Strange

    Then you will need to show the math that demonstrates that that can produce the observed acceleration.

    No,I will leave the math part to mathematicians like you.I can't live with the fact that we are not able explain dark energy or dark matter.I know it is just a matter of time,but can't wait.I like to imagine "black holes" as dark energy stars.It is said that if black holes are isolated, they will gradually get evaporated.When that happens the matter or energy which is supposed to be in them also vanishes with them forever?.(maybe they are getting trapped in a space loop bubble which expands into another universe or something in the hyperspace )
    And when two black holes collide a huge amount of energy is released as they combine together,Where is this energy coming from?Is it coming from the accretion disk or is it from the insides of either one, or both of these black holes(no,that's crazy,right?).

    @HI, Markus Hanke

    Yes, all forms of energy interact with gravity; this goes for mass, but also for things like electromagnetic fields, strains and stresses etc etc.
    By energy I don't mean any of the observable forms of it.What was energy like when photons and particles like that were not even in the picture,I mean dark energy was there before the first light ray,right?
    I like to imagine dark energy as pure energy and all other types of energy as condensed forms of it...be it light or heat.Only the more condensed forms of energy actively interact with matter which is again super dense form of energy.

    You assume wrongly. Dark energy is constant everywhere in space ( unlike dark matter ), which is why it can be associated with the cosmological constant in Einstein's field equations.
    As far as I know the cosmological constant view see dark energy as some kind of negative gravity.Anti matter also creates this effect,right?
    But a minority believe that it is in Quintessence state.
    quintessence can be either attractive or repulsive depending on the ratio of its kinetic and potential energy.
    attractive(dark matter gravity effect)
    repulsive(space time stretch)??

    Are you guys physicists?I am not!just a science enthusiast here.
    Last edited by MaxPayne; 10-07-2013 at 04:14 PM. Reason: spelling mistake
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  7. #7  
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    Quote Originally Posted by MaxPayne View Post
    I like to imagine "black holes" as dark energy stars.
    No, that is certainly not the case. Black holes are the end result of a gravitational collapse, and has nothing to do with DE.

    When that happens the matter or energy which is supposed to be in them also vanishes with them forever?
    No, it radiates off via Hawking radiation. Remember that energy can never be created or destroyed, it is always conserved.

    And when two black holes collide a huge amount of energy is released as they combine together
    Actually, I don't think that's what happens.

    What was energy like when photons and particles like that were not even in the picture,I mean dark energy was there before the first light ray,right?
    Yes, dark energy would have been present before the symmetry breaking process through which photons came into existence in the early universe.

    I like to imagine dark energy as pure energy and all other types of energy as condensed forms of it
    I'm afraid that makes little sense - as I mentioned, DE is constant everywhere, it cannot be converted or "condensed" into other types.

    As far as I know the cosmological constant view see dark energy as some kind of negative gravity
    Not really, no. Gravity is always attractive. What the cosmological constant does is merely alter the dynamics of the cosmological expansion, thereby accelerating its rate.

    Anti matter also creates this effect,right?
    No, anti matter gravitates just like normal matter does.

    Are you guys physicists?
    The majority of us are just interested amateurs.
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    No, that is certainly not the case. Black holes are the end result of a gravitational collapse, and has nothing to do with DE.
    Yes,I know that its the result of gravitational collapse of gigantic stars,but we can't be sure(not the collapse part,but "it has nothing to do with dark energy" part).The dark energy star may not be the leading theory but it makes complete sense when we link it with the expansion of Universe and dark matter's gravity(for me at least,maybe i am over imaginative).

    No, it radiates off via Hawking radiation. Remember that energy can never be created or destroyed, it is always conserved.
    It is one of the leading theories,but have they been able to detect it(The HoRays??DE is not constant,it is constantly increasing inside a given volume of spaceright?

    No, anti matter gravitates just like normal matter does.
    Can you give me some links regarding this?I want to learn more about anti matter gravitation.Interaction between two anti particles,a matter and an anti matter particle etc,and at microscopic scale the electromagnetic forces overwhelms gravity controlling the interactions.The gravitational behavior of anti matter has not been studied conclusively because it is so difficult since anti matter don't seem to form particles heavier than atoms(molecules maybe).This goes to show that anti matter can't come together to form larger bodies like ordinary matter does.So I am assuming that they have negative mass which causes them to repel each other(anti gravity??)

    it cannot be converted or "condensed" into other types.
    Again!We really don't know if this is what happening out there.We can't say no to any possibility unless we have proven it wrong.I mean it is imagination which unearths possibilities for mathematical verification,right?

    I'm afraid that makes little sense - as I mentioned, DE is constant everywhere, it cannot be converted or "condensed" into other types.
    As you have invoked the conservation of energy principle,Is dark energy concept consistent with it?Mysterious energy that is constantly being made; causes expansion of space time in turn creating more expansion?



    And when two black holes collide a huge amount of energy is released as they combine together
    Then?what is really happening there? Isn't gravity wave an kind of energy wave..just like any electromagnetic wave?.When black holes collide gravity waves are produced.

    The majority of us are just interested amateurs.
    Cool,I can breath easy now!!pssshh
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  9. #9  
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    Quote Originally Posted by MaxPayne View Post
    The dark energy star may not be the leading theory but it makes complete sense when we link it with the expansion of Universe and dark matter's gravity(for me at least,maybe i am over imaginative).
    Hm, I don't really see the connection, to be honest. Also, DE is not a form of matter, so I don't know how it is supposed to form a star.

    DE is not constant,it is constantly increasing inside a given volume of spaceright?
    DE density is constant, so in an increasing volume of space the total DE of course increases - but then, so does the negative work it does ( "pressure" ), so the overall amount of energy is exactly zero, and never changes.

    Can you give me some links regarding this?
    Have a look here : Gravitational interaction of antimatter - Wikipedia, the free encyclopedia
    Final confirmation is still outstanding, but to me there are strong theoretical arguments indicating that antimatter gravitationally behaves just like matter.

    So I am assuming that they have negative mass
    Careful here - antimatter is not negative mass ( whatever that means ) !

    I mean it is imagination which unearths possibilities for mathematical verification,right?
    True, but the imagination needs to take into account what we already know, and built on that basis. Since DE is a property of space-time itself, it being able to be converted into other types of energy would create all manner of problems, e.g. violations of energy-momentum conservation.

    Is dark energy concept consistent with it?
    Yes it is...otherwise it would not have been put forward as a valid cosmological model.

    Mysterious energy that is constantly being made; causes expansion of space time in turn creating more expansion?
    Yes. It may seem paradoxical at first, but you must remember that the energy and the work it does on its surroundings have opposite sign; total energy is thus automatically conserved. This can be shown mathematically also.

    When black holes collide gravity waves are produced.
    That's true, both before and after the merger. What is the precise question ? I should mention here that energy is a tricky concept in General Relativity...
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  10. #10  
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    Careful here - antimatter is not negative mass ( whatever that means ) !

    I don't know,maybe it causes a bulge in space time instead of a depression

    Don't know why? we don't see anti matter nowadays.Maybe they are out there,but are unable to come together to form larger objects like stars;hence they only exist as microscopic particles. Anti gravity caused by negative mass could be a reasonable explanation..

    Hm, I don't really see the connection, to be honest. Also, DE is not a form of matter, so I don't know how it is supposed to form a star.
    lol!! Dark energy didn't come together to form DE stars(); in fact "black holes(dark energy stars)" are producing it from the matter that it sucks in.(According to me ie).Mass can be converted to energy?And energy can be changed from one form to another.Since DE is a form of energy,the possibility of mass getting converted to DE inside "black holes" can't be ruled out .

    (from wiki)Antigravity: Some authors argue that antimatter repels matter with the same magnitude as matter attracts matter (see below). This should not be confused with the many other speculative phenomena that may also be called 'anti-gravity'
    I am not saying that matter and antimatter should necessarily repel each other,they should interact normally due to the dominant electromagnetic force,just saying that antimatter might repel anti matter,just like electrons repel each other.

    I have drawn a pic,just take a look.butterfly.jpg
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  11. #11  
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    Quote Originally Posted by MaxPayne View Post
    I don't know,maybe it causes a bulge in space time instead of a depression
    Negative energy would have such an effect, but the point is that antimatter is not negative energy ( "exotic matter" ); they are two different things.

    Anti gravity caused by negative mass could be a reasonable explanation
    A reasonable explanation for what ?

    Mass can be converted to energy?
    Yes.

    And energy can be changed from one form to another
    Yes.

    Since DE is a form of energy,the possibility of mass getting converted to DE inside "black holes" can't be ruled out
    While we can't rule it out, this question is largely academic, simply because what happens beyond the event horizon stays there. The region of space-time enclosed by the event horizon has no causal connection to the rest of the universe.
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    Negative energy would have such an effect, but the point is that antimatter is not negative energy ( "exotic matter" ); they are two different things.
    How do we know that anti matter is not a kind of exotic matter?A positron weighs much less than a proton,but it still carries the same charge.Can we still say that they are made up of the same basic thing?A positron is like a positive electron or a lack of an electron(say)right?Since mass is just concentrated energy,a positron should be a concentrate of negative energy.As far as I know exotic matter is purely theoretical but yet mathematically plausible(maybe it's anti matter,but we are not realizing it).A bulge in space time would be equivalent to a depression in it,if we turn the clock the other way.Matter and anti matter would annihilate each other with release of a lot of energy.Another way to explain this would be like "matter and antimatter annihilate each other absorbing a lot of negative energy in the process.Since anti matter can be thought of like matter travelling backwards in time,absorption of negative energy would seem like release of negetive energy from it's perspective.(my head is spinning)

    If you are right then why we don't see any stars made out of anti matter?More matter in the Universe than anti matter?That theory violates the symmetry of the Universe.
    I think the negative gravity is what caused them to disperse so far and wide apart that we are unable to observe them. Isn't it the gravity of normal matter that kept them together to form all this?
    no causal connection to the rest of the universe
    hmmm,we don't know if there is any.The falling matter doesn't increase the mass of the black hole,that means they are either going out of this Universe or getting converted to some kind of undetectable form of energy that is constantly leaving it(hawking radiation is too little too slow,not to increase the mass)right?.
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  13. #13  
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    Quote Originally Posted by MaxPayne View Post
    How do we know that anti matter is not a kind of exotic matter?
    Antimatter can be produced in particle accelerators, and it takes a positive amount of energy to do so. Hence antimatter has a positive energy density, and is thus not exotic matter.

    A positron weighs much less than a proton
    A positron is the antiparticle of an electron, not a proton.

    Since mass is just concentrated energy,a positron should be a concentrate of negative energy
    It isn't. The only thing which comes even close to "negative energy" is the Casimir Effect.

    If you are right then why we don't see any stars made out of anti matter?
    Yes, that is one of the unresolved questions in physics - why is there more matter than antimatter ? I'm afraid I don't have the answer

    hmmm,we don't know if there is any.
    Actually, we do know this with some confidence - it's a direct result of the geometry of space-time itself, and the laws of gravity. Black holes could not exist in the first place if this weren't so.

    The falling matter doesn't increase the mass of the black hole
    Yes it does.

    (hawking radiation is too little too slow,not to increase the mass
    Hawking radiation decreases the mass of the black hole; however, it actually originates just above the beyond horizon. The precise mechanism is pretty complicated though, and has to do with quantum field theories in curved space-times.
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    Antimatter can be produced in particle accelerators, and it takes a positive amount of energy to do so. Hence antimatter has a positive energy density, and is thus not exotic matter.
    Yes,I agree with you,but remember that they are paired up with their corresponding matter particles when they are formed.The matter produced in the process might account for this positive energy loss.Energy liberated during the process would effect antimatter formartion??

    Radioactive decay of sodium 22 can happen in two ways

    Na 22 ---->positron+Neutrino+Ne 22+photon(by positron emission)
    Na 22 + Electron ----->Neutrino+Ne22+photon(by electron capture)
    Although charge is getting conserved,energy is not
    So,Energy/mass wise also,an electron = - (positron)???Right?
    Or maybe I am missing something here..idk

    A positron is the antiparticle of an electron, not a proton.
    Exactly my point,its not a proton

    Hawking radiation decreases the mass of the black hole; however, it actually originates just above the beyond horizon. The precise mechanism is pretty complicated though, and has to do with quantum field theories in curved space-times.
    friction between sub atomic particles in the accretion disk?does that work here?
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  15. #15  
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    Quote Originally Posted by MaxPayne View Post
    How do we know that anti matter is not a kind of exotic matter?A positron weighs much less than a proton,but it still carries the same charge.Can we still say that they are made up of the same basic thing?A positron is like a positive electron or a lack of an electron(say)right?Since mass is just concentrated energy,a positron should be a concentrate of negative energy.
    Positrons don't have negative energy or negative mass. As can be trivially seen from conservation laws. When an electron and a positron annihilate, they produce two photons with a total energy of 1.2 MeV which is exactly the energy equivalent of the masses of the two particles. If positrons had negative energy then the result of the annihilation would be ... nothing.

    More matter in the Universe than anti matter?That theory violates the symmetry of the Universe[/B].
    That is one of the major outstanding questions in cosmology.

    no causal connection to the rest of the universe
    hmmm,we don't know if there is any.
    We do, because that is what defines a black hole. If there is not an event horizon then it isn't a black hole.

    The falling matter doesn't increase the mass of the black hole
    Yes it does.
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    If positrons had negative energy then the result of the annihilation would be ... nothing
    Why nothing?It should release +ve energy.The energy released is in the form of photons;anti photons and photons are the same thing.It would make no sense if I say electron positron annihilation results in the production of a photon and an anti photon,coz they look the same.Any photon can be an anti photon,photons are the basic particles that is unaffected by time.It is basically standing still in time.We are the ones who is travelling forward in time,not the photon.So it appears as if it is carrying +ve energy,when it actually has no energy at all.If we were travelling back in time, photons would also appear to be travelling back in time as anti photons(?).If we measure it's energy, then it should read - x MeV.
    Trying to violate conservation of energy principle by combining an electron and positron is a bad ploy.Making antimatter matter pair spontaneously is only possible if you can stay neutral in time.GOD?

    The falling matter doesn't increase the mass of the black hole
    Yes it does.
    For an observer it doesn't. Since any object will take almost infinite time to fall into a black hole, the equivalent mass increase should also take an infinite time from the observer's frame of reference(Unless gravity/gravitons can somehow travel faster than light).Right???
    Last edited by MaxPayne; 10-12-2013 at 06:23 AM.
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    Quote Originally Posted by MaxPayne View Post
    Yes,I agree with you,but remember that they are paired up with their corresponding matter particles when they are formed
    No, that is not necessarily true. The positron emission process you quoted below is a good example of the contrary.

    Energy liberated during the process would effect antimatter formartion??
    I am not sure what you mean by this.

    Although charge is getting conserved,energy is not
    Why do you think energy is not conserved ?

    So,Energy/mass wise also,an electron = - (positron)???Right?
    No, the positron has positive mass, and positive electric charge; to make a long story short, both electrons and positrons have positive energy.

    Exactly my point,its not a proton
    I am really not sure what you are trying to say. Positrons are the antiparticles of electrons; both of these are elementary fermions. Protons are composite hadrons. I don't really get what you are trying to say...?

    friction between sub atomic particles in the accretion disk?does that work here?
    No, Hawking radiation is an effect of quantum fields in highly curved space-times.
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    Quote Originally Posted by MaxPayne View Post
    Why nothing?It should release +ve energy
    No - if you combine "negative energy" with the exact same amount of positive energy, the result is exactly zero. There wouldn't be anything emitted.

    .It would make no sense if I say electron positron annihilation results in the production of a photon and an anti photon
    Photons are their own antiparticles, so "antiphotons" do not exist. The annihilation process simply results in the emission of two photons, for reasons of momentum conservation.

    It is basically standing still in time.
    That isn't really correct, because photons propagate along null geodesics in space-time, and hence the notion of proper time is not defined for them. Mind you, one can still affinely parametrize these null geodesics in other ways.

    So it appears as if it is carrying +ve energy,when it actually has no energy at all.
    That's wrong, photons carry both energy ( E=hf ) and momentum ( p=hk ).

    Trying to violate conservation of energy principle by combining an electron and positron is a bad ploy
    No one is doing that : e(-) + e(+) = y + y

    Nothing is being violated at all in this process.

    For an observer it doesn't. Since any object will take almost infinite time to fall into a black hole, the equivalent mass increase should also take an infinite time from the observer's frame of reference(Unless gravity/gravitons can somehow travel faster than light).Right???
    For an external observer a mass increase manifests in the outward expansion of the event horizon; that happens instantaneously, at precisely the (local) moment when the additional mass crosses the event horizon. Since changes in space-time curvature then propagate at the speed of light, the external observer will measure same after a finite time.
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    We can't go on arguing like this...

    No - if you combine "negative energy" with the exact same amount of positive energy, the result is exactly zero. There wouldn't be anything emitted.
    And how do you combine negative energy with positive energy...It is like trying to collide two cars travelling away from each other on separate highways.Photons don't interact with each other in a system where there is time or vibration of particles.

    Anti matter will only yield positive energy upon it's destruction.That is because you are actually creating anti matter, not destroying it, when you are destroying it.I am talking about reverse causality here.

    Photons are their own antiparticles, so "anti photons" do not exist. The annihilation process simply results in the emission of two photons, for reasons of momentum conservation.
    Exactly,photon is equivalent to it's anti particle.

    so "anti photons" do not exist
    I can't agree with this.Anti photons are photons...hmmm,
    Okay,I call apple; Seb , but you prefer to call it APPLE.It will sound ridiculous to you if I say that there are only sebs and apples don't exist.
    Anti Photons appear like photons to an observer of matter origin.Photons would appear like anti photons to an observer of antimatter origin.They look the same anyways!.

    So it appears as if it is carrying +ve energy,when it actually has no energy at all.
    That's wrong, photons carry both energy ( E=hf ) and momentum ( p=hk ).
    Yes,.....E=hf; frequency is a function of time;it is not defined in a state where there is no time.(Are you reading the whole thing)
    p =hk; when time is still,p=0=hk;but h*k=/=0(can you imagine photons zipping through space without time) .Means the equation is only valid in places where time exists.

    No one is doing that : e(-) + e(+) = y + y
    I agree with that, i am just saying that one of the photon is really an anti photon.
    You can't reverse this process in forward time to produce a matter-anti matter pair.The photons will pass right through each other without any collision.Think about it.

    For an external observer a mass increase manifests in the outward expansion of the event horizon; that happens instantaneously, at precisely the (local) moment when the additional mass crosses the event horizon. Since changes in space-time curvature then propagate at the speed of light, the external observer will measure same after a finite time.
    That is correct!But at some point in time,the event horizon would cross the last seen position of the of the object due to it's expansion.We will notice that object is no longer there, only then;But to us remote observers expansion happened first,only then did the object go in.But from the object's perspective it had gone in first,expansion happened later.Does that violates causality?
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  20. #20  
    KJW
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    Quote Originally Posted by MaxPayne View Post
    The falling matter doesn't increase the mass of the black hole
    Yes it does.
    For an observer it doesn't. Since any object will take almost infinite time to fall into a black hole, the equivalent mass increase should also take an infinite time from the observer's frame of reference(Unless gravity/gravitons can somehow travel faster than light).Right???
    If one measures the gravitation far from the blackhole, it will include the contribution from the infalling matter even if it is still outside the event horizon.
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    Hi,KJW
    Thanks for Joining us.

    If one measures the gravitation far from the blackhole, it will include the contribution from the infalling matter even if it is still outside the event horizon.

    But how can things outside the event horizon contribute to a black holes total mass/gravity?
    Is it just an illusion?
    Like in the case of lightning and thunder,from a distance we see lightning occurring first; then only we hear of the thunder.But actually they are produced simultaneously.Light is faster than sound...Applying the same logic here would mean that gravity is faster than light,But actually they both have the same velocity,since gravitational waves have never been observed to be travelling at FTL speeds.
    Or does this phenomenon actually violate the causality principle?
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    Quote Originally Posted by MaxPayne View Post
    Hi,KJW
    Thanks for Joining us.

    If one measures the gravitation far from the blackhole, it will include the contribution from the infalling matter even if it is still outside the event horizon.

    But how can things outside the event horizon contribute to a black holes total mass/gravity?
    Is it just an illusion?
    I'm not talking about the mass of the blackhole itself. I'm talking about the mass of the total system, which is all that one can measure (gravitationally) far from the system.
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    I'm not talking about the mass of the blackhole itself. I'm talking about the mass of the total system, which is all that one can measure (gravitationally) far from the system.

    Hmmm.....then black holes should have infinite mass and gravity.We are all outside the black hole hence we are also the part of the system. Is it safe to say that we are also contributing to black hole's gravity?.What if some black hole has our names written on it?no matter how hard we try to escape from it's grip, we will still fall into it.
    Free will?
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    Quote Originally Posted by MaxPayne View Post
    Anti matter will only yield positive energy upon it's destruction.That is because you are actually creating anti matter, not destroying it, when you are destroying it.
    This statement does not appear to making any sense.

    I can't agree with this.Anti photons are photons...hmmm,
    Yes, the photon is its own anti-particle. The reason is to be found in the fact that the photon is the gauge boson associated with the Abelian U(1) symmetry group of quantum electrodynamics.

    Photons would appear like anti photons to an observer of antimatter origin.
    Like I said above - photons are their own antiparticles.

    Yes,.....E=hf; frequency is a function of time;it is not defined in a state where there is no time.(Are you reading the whole thing)
    p =hk; when time is still,p=0=hk;but h*k=/=0(can you imagine photons zipping through space without time) .Means the equation is only valid in places where time exists.
    The equation is always valid for all local observers. Like I explained earlier, photons are just null geodesics in space-time, and you can't separate out the "time" component from space-time.

    I agree with that, i am just saying that one of the photon is really an anti photon.
    See above. Both are just photons.

    You can't reverse this process in forward time to produce a matter-anti matter pair.
    Yes you can - any given photon can, given the right conditions, transition into a particle-antiparticle pair, such as an electron + positron. This is called pair production.

    Does that violates causality?
    No, because time is always a local phenomenon, so both observers are right in their own frames of reference. There is no conflict.
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    Quote Originally Posted by MaxPayne View Post
    Hmmm.....then black holes should have infinite mass and gravity
    No, that does not follow. Only objects which are gravitationally bound to the black hole can be considered part of that system. Where one draws the line is a somewhat arbitrary choice that depends on the boundary conditions of the scenario in question, but the total energy of the system is always finite.
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    :cool
    No, that does not follow. Only objects which are gravitationally bound to the black hole can be considered part of that system. Where one draws the line is a somewhat arbitrary choice that depends on the boundary conditions of the scenario in question, but the total energy of the system is always finite.

    I think we are all connected to every black hole in the Universe. But I got your point there.

    The equation is always valid for all local observers. Like I explained earlier, photons are just null geodesics in space-time, and you can't separate out the "time" component from space-time.
    you can't separate out the "time" component from space-time.

    Did I say that we could?my bad then!You can't move through space without moving through time.Object travelling at the speed of light is equivalent to an object not moving in space time.You can actually stop time by stopping the motion of every object in the Universe.I think Cryopreservation somehow works on the same principle.
    Alright!So what do you think ?why are we travelling forward in time?i mean in a world where cause precedes effect?I am quite convinced that anti matter is really matter moving back in time.And that for a hypothetical organism made up of anti matter, effect precedes cause.
    photons are just null geodesics in space-time
    True!The proper time of photons on Null geodesic is ZERO.My inference is that photon's don't posses any energy in a rest frame.

    The equation is always valid for all local observers.
    *To all observers travelling forward in time with a velocity<<light speed.Right??What about an observer travelling at light speed.(from photon's point of view)

    Yes you can - any given photon can, given the right conditions, transition into a particle-antiparticle pair, such as an electron + positron. This is called pair production.
    Yes,That is how they create anti particles in particle accelerator labs..right?But again!!you didn't create the pair just by using the photon of required energy.
    Without a nucleus to absorb momentum, a photon decaying into electron-positron pair (or other pairs for that matter) can never conserve energy and momentum simultaneously-Wiki
    I don't know?Do we require any such external "catalyst" to trigger electron positron annihilation(really,Idk..tell me if there is any)?Thus the pair formation is not a reverse process of electron positron annihilation.If it was!the photons will slow down spontaneously at the point of impact without any external help.The true reverse process can only occur if we reverse the time.

    Does that violates causality?
    No, because time is always a local phenomenon, so both observers are right in their own frames of reference. There is no conflict.
    Yes,there is a conflict!!!if the two ever meet then they are bound to have an argument over which event is cause and which ones the effect.That is in itself is a blot on deterministic causality,because they are both right.A third party can't determine the cause without actually observing the event from his own frame of reference.
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    Quote Originally Posted by MaxPayne View Post
    You can't move through space without moving through time.
    Yes, correct.

    Object travelling at the speed of light is equivalent to an object not moving in space time.
    That's not correct, at least not in the way you express it. First of all, nothing "moves" in space-time as such, it is a static (3+1) dimensional scenario we are considering here. However, we can look at the ( static ) world lines of objects in space-time, and find that at each point we can define a unit tangent vector with respect to some affine parameter of the curve; for time-like geodesics that is just the proper time, for null geodesics it will be another affine parameter. In any case, the main point is that the magnitude of this tangent vector is always exactly c, at all points. What this means is that all objects can be considered to have an intrinsic velocity in space-time, with a magnitude of exactly c; all that changes is how "movement through space" relates to "movement through time".

    I understand what you are trying to say - an object at relative rest moves only through time, but not through space ( in a local sense ); the other extreme would then need to be a photon moving only through space, but not through time. You need to be careful though to realise that a photon is not a valid frame of reference, hence the notion of "proper time" is not defined for it.

    True!The proper time of photons on Null geodesic is ZERO.My inference is that photon's don't posses any energy in a rest frame.
    Actually, the notion of proper time is not defined for photons. What is defined though is a photon's energy, which is most definitely not zero. Energy is also not a function of proper time - I am not sure where you get that idea.

    *To all observers travelling forward in time with a velocity<<light speed.Right??What about an observer travelling at light speed.(from photon's point of view)
    A photon is not a valid frame of reference; there are no observers travelling at the speed of light.

    Yes,That is how they create anti particles in particle accelerator labs..right?
    It is one of many ways to create positrons, yes. There are other, easier methods though.

    I don't know?Do we require any such external "catalyst" to trigger electron positron annihilation(really,Idk..tell me if there is any)?Thus the pair formation is not a reverse process of electron positron annihilation.If it was!the photons will slow down spontaneously at the point of impact without any external help.The true reverse process can only occur if we reverse the time.
    I am sorry, but I don't understand what you are asking. All I can say to this at the moment is that photons cannot accelerate/decelerate, so they never "slow down".

    Yes,there is a conflict!!!if the two ever meet then they are bound to have an argument over which event is cause and which ones the effect
    So what ? Let them argue - like I said, there is no requirement in globally curved space-times for observers in different reference frames to agree on anything to do with times and lengths. All notions of space and time are local notions only, they aren't globally valid. It is therefore not a problem for observers to disagree. I understand that this is highly non-intuitive, because it runs counter to what we are used to from our own non-relativistic world of everyday experiences - we tend to think that it is impossible for observers to disagree on notions such as causality, measurements of length, times etc etc; yet it is what inevitably happens in curved space-times such as around black holes. Trust me, this caused me a lot of issues as well when I first started to learn about relativity, but once you keep studying the geometry that underlies these principles, it becomes quite clear and obvious as to why this must be so. It is all just geometry, really.
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    Actually, the notion of proper time is not defined for photons. What is defined though is a photon's energy, which is most definitely not zero. Energy is also not a function of proper time - I am not sure where you get that idea.
    So, What gives energy to a photon?

    A photon is not a valid frame of reference; there are no observers travelling at the speed of light.
    If we create a camera made out of photons and accelerate it to c....please do answer to this.

    I am sorry, but I don't understand what you are asking. All I can say to this at the moment is that photons cannot accelerate/decelerate, so they never "slow down".
    But we have stopped the motion of photons already, and it appears to be moving in time as well.

    Trust me, this caused me a lot of issues as well when I first started to learn about relativity, but once you keep studying the geometry that underlies these principles, it becomes quite clear and obvious as to why this must be so. It is all just geometry, really.
    Yes, I understand...
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    Quote Originally Posted by MaxPayne View Post
    But we have stopped the motion of photons already, and it appears to be moving in time as well.
    I assume you are thinking of this: Phys. Rev. A 87, 031801 (2013): Light storage on the time scale of a minute
    This is described by New Scientist in one of their typically misleading headlines as, "Light completely stopped for a record-breaking minute."

    Photons have not been stopped, light has. Even that is a poor description (typical of science journalists). The light/photons are stored by the material and then released. I have seen one good description of this experiment.Unfortunately I can't find it now.
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    I assume you are thinking of this: Phys. Rev. A 87, 031801 (2013): Light storage on the time scale of a minute
    This is described by New Scientist in one of their typically misleading headlines as, "Light completely stopped for a record-breaking minute."

    Photons have not been stopped, light has. Even that is a poor description (typical of science journalists). The light/photons are stored by the material and then released. I have seen one good description of this experiment.Unfortunately I can't find it now.

    Thanks strange!!......you mean they are still moving inside the material at light speed? so whats new in it? Lasers also does this right(for a very small time.Why we so excited about this "new?" discovery?

    I heard the rumor that we have been able to create a new kind of matter using photons???God knows what they really mean by that.

    http://phys.org/news/2013-09-scienti...fore-seen.html
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    Quote Originally Posted by MaxPayne View Post
    So, What gives energy to a photon?
    Its momentum. More accurately, the energy is an intrinsic property of the photon itself.

    If we create a camera made out of photons and accelerate it to c....please do answer to this.
    You couldn't, because photons don't self-interact - you can't combine them into structures such as atoms and molecules. A "photonic camera" is thus a meaningless concept. I appreciate what you are trying to do and ask, but it just isn't a physically meaningful question.

    But we have stopped the motion of photons already, and it appears to be moving in time as well.
    Sorry, I don't understand...?
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    You couldn't, because photons don't self-interact - you can't combine them into structures such as atoms and molecules. A "photonic camera" is thus a meaningless concept. I appreciate what you are trying to do and ask, but it just isn't a physically meaningful question.
    Scientists create never-before-seen form of matter

    But we have stopped the motion of photons already, and it appears to be moving in time as well.
    Sorry, I don't understand...?
    I thought they actually stopped the photon from moving. I was wrong.
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    Is matter getting converted into dark energy inside black holes?
    I would like to come back to this for a minute, and I wish to retract some of what I had stated earlier. The above idea is not mainstream in any sense of the word, however, it did invoke my curiosity, so I thought about it some more; if we allowed the density of DE to vary locally, e.g. in the interior of a black hole, it should in theory be possible to create a system in a stable equilibrium. The basic setup would be that the cosmological constant in the interior region of the BH becomes very large, creating a negative pressure that "pushes outwards" against gravity, just like it does on cosmological scales where it accelerates the expansion. The result would be an object the interior of which is a perfect vacuum; infalling matter would initially behave just like at a "normal" BH, but, having crossed the event horizon, would slow due to the presence of DE, and would eventually come to rest at a thin shell surrounding the otherwise empty interior region. Matter here would likely exist in its highest state of degeneracy ( whatever that will turn out to be ), but will nonetheless be normal physical matter/energy.

    Such an object should from the outside be indistinguishable from a "normal" black hole, yet the interior region would be empty, and no singularity would form. I would be very interesting to see what the metric and geodesic structure for the interior region of such an object would look like, and whether this could indeed yield a stable equilibrium. I don't know though if, once we allow the cosmological constant to cease being constant, this would "break" anything in the maths or physics - further investigation is most definitely needed.

    I must admit though that on further thought it is an interesting idea, and I don't say that very often or lightly, considering the kind of stuff that gets posted on these forums on a daily basis. This could just work.
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    Quote Originally Posted by Markus Hanke View Post
    I would like to come back to this for a minute, and I wish to retract some of what I had stated earlier. The above idea is not mainstream in any sense of the word, however, it did invoke my curiosity, so I thought about it some more; if we allowed the density of DE to vary locally, e.g. in the interior of a black hole, it should in theory be possible to create a system in a stable equilibrium. The basic setup would be that the cosmological constant in the interior region of the BH becomes very large, creating a negative pressure that "pushes outwards" against gravity, just like it does on cosmological scales where it accelerates the expansion. The result would be an object the interior of which is a perfect vacuum; infalling matter would initially behave just like at a "normal" BH, but, having crossed the event horizon, would slow due to the presence of DE, and would eventually come to rest at a thin shell surrounding the otherwise empty interior region. Matter here would likely exist in its highest state of degeneracy ( whatever that will turn out to be ), but will nonetheless be normal physical matter/energy.

    Such an object should from the outside be indistinguishable from a "normal" black hole, yet the interior region would be empty, and no singularity would form. I would be very interesting to see what the metric and geodesic structure for the interior region of such an object would look like, and whether this could indeed yield a stable equilibrium. I don't know though if, once we allow the cosmological constant to cease being constant, this would "break" anything in the maths or physics - further investigation is most definitely needed.

    I must admit though that on further thought it is an interesting idea, and I don't say that very often or lightly, considering the kind of stuff that gets posted on these forums on a daily basis. This could just work.
    Has anyone actually derived the metric for a static blackhole in a spacetime with a cosmological constant?
    A tensor equation that is valid in any coordinate system is valid in every coordinate system.
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    Quote Originally Posted by KJW View Post
    Has anyone actually derived the metric for a static blackhole in a spacetime with a cosmological constant?
    Isn't that just the Nariai solution for de Sitter-Schwarzschild space-time ?

    de Sitter
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    Quote Originally Posted by Markus Hanke View Post
    Isn't that just the Nariai solution for de Sitter-Schwarzschild space-time ?

    de Sitter
    I hadn't come across that... thanks
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    Quote Originally Posted by KJW View Post
    I hadn't come across that... thanks
    I'd be rather interested to see though whether this solution also works if the cosmological constant is allowed to vary across space-time, i.e. in cases where it isn't actually constant at all.
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    Hello Again,
    Another very silly thought
    Thanks for looking into this again.
    But even if we find Einstein's cosmo constant to be "constant" everywhere. That could just be because of the loss of energy from the visible(?) Universe. Many of us will not like the idea of energy loss from the Universe to a higher dimensional hyperspace (?) with many such Universe(s) in it.So In order to make up for the lost energy and to keep total energy of the Universe constant(don't ask me why?) the space gives up it's energy to the Universe causing it to expand.(the energy was holding it together..Kind of like Binding Energy in the case of nucleus)Thus DE is actually negative energy which is causing the expansion of space.

    The reason why I like to connect black holes with space expansion is because in black holes mass is lost for the Universe(because it can no longer affect The Universe)
    and in case of DE, it is energy coming into our Universe. Unifying both of these mysteries certainly quenches my thirst.
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    Quote Originally Posted by MaxPayne View Post
    Thanks strange!!......you mean they are still moving inside the material at light speed? so whats new in it? Lasers also does this right(for a very small time.Why we so excited about this "new?" discovery?
    The photons are absorbed by atoms in the material. So they no longer exist. But all the information is stored in the atomic structure. And then some time (as in many seconds) later they are "released". The remarkable thing is the new photons carry on in the same direction, etc. as the original ones. What is novel about this is the length of time they are stored for.

    I heard the rumor that we have been able to create a new kind of matter using photons???God knows what they really mean by that.
    More sloppy reporting

    I haven't read the details of this so can't really comment. But apparently pairs of photons can be made to interact within certain materials in a way that makes them appear to have mass... or something....
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    Quote Originally Posted by MaxPayne View Post
    The reason why I like to connect black holes with space expansion is because in black holes mass is lost for the Universe(because it can no longer affect The Universe)
    The mass is not lost. The black hole still has the mass and still affects the rest of the universe in exactly the same way that that mass always did.
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    The mass is not lost. The black hole still has the mass and still affects the rest of the universe in exactly the same way that that mass always did.
    Yes,True...I didn't think about it.Gravity of the black hole should increase as more matter falls into it.This should increase it's size, as the gravity increases it will pull in even more matter.Eventually all that remains will be black holes. Eventually they will all disappear.There will be nothing except expanding space and radiations send out by these black holes.
    will all this happen before the big rip

    The photons are absorbed by atoms in the material. So they no longer exist. But all the information is stored in the atomic structure. And then some time (as in many seconds) later they are "released". The remarkable thing is the new photons carry on in the same direction, etc. as the original ones. What is novel about this is the length of time they are stored for.
    Atomic structure???? But it is a known fact that electrons absorb photons to get excited and when they de-excites they will release the photon..And that photon must be equivalent to the absorbed photon(?right)...So basically all that they had done was "managing to keep electron at excited state for an extended period of time".
    Also rest photon would mean extending this state indefinitely. But that is also a great achievement, take nothing away from them.

    I heard the rumor that we have been able to create a new kind of matter using photons???God knows what they really mean by that.
    More sloppy reporting
    I haven't read the details of this so can't really comment.
    www.independent.co.uk/news/.../scientists-bind-photons-together-to-create-new-state-of-matter-comparable-to-lightsabers-8841612.html


    But apparently pairs of photons can be made to interact within certain materials in a way that makes them appear to have mass... or something....
    As per you
    1) particles need to have mass in order to interact with each other.
    2) photons can be given mass so as to create complex objects with it.

    but to have mass, we need to slow them done. Or, is it the atoms that absorbed those photons that are interacting with each other?
    I don't think you should blame the journalists for this, scientists are giving them these ideas! In order to raise public interest and to draw in funds for their future programs.
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    Quote Originally Posted by Strange View Post
    But apparently pairs of photons can be made to interact within certain materials in a way that makes them appear to have mass... or something....
    They don't appear to have mass - all that is really happening here is that two photons get entangled in such a way that makes them "behave" like a single entity. The details aren't easy to understand ( I don't get all of it either ), but it basically boils down to entanglement.
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    They don't appear to have mass - all that is really happening here is that two photons get entangled in such a way that makes them "behave" like a single entity. The details aren't easy to understand ( I don't get all of it either ), but it basically boils down to entanglement.
    The things don't have mass, spin(?), charge...which property(s) getting entangled? Energy, frequency, polarization?
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    Quote Originally Posted by MaxPayne View Post
    Yes,True...I didn't think about it.Gravity of the black hole should increase as more matter falls into it.This should increase it's size, as the gravity increases it will pull in even more matter.
    Black holes are no more likely to do that than any other object of the same mass.

    I don't think you should blame the journalists for this, scientists are giving them these ideas! In order to raise public interest and to draw in funds for their future programs.
    I wouldn't mind so much if science journalists explicitly said, "this is a crude and hugely inaccurate simplification based on analogies". I have seen too many people claiming that, for example, the complex math of Hawking Radiation (which is so far beyond me that it is equivalent to magic) must be wrong because they have read a pop-science article; they refuse to accept that the problem might be with the simplified story they have read.
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    Quote Originally Posted by MaxPayne View Post
    The things don't have mass, spin(?), charge...which property(s) getting entangled? Energy, frequency, polarization?
    My guess would be that it's the polarization states which get entangled.
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    I wouldn't mind so much if science journalists explicitly said, "this is a crude and hugely inaccurate simplification based on analogies". I have seen too many people claiming that, for example, the complex math of Hawking Radiation (which is so far beyond me that it is equivalent to magic) must be wrong because they have read a pop-science article; they refuse to accept that the problem might be with the simplified story they have read
    Well!!It is because people don't want to believe in magic. I am glad that you understand and appreciate Hawking's mathematics on black hole. Many people including me don't have a clue and it's implications on physical world appears bizarre. I thinking contrasting views are always helpful. If one way of looking at an object doesn't reveal everything about that object,then you got to look at it from certain different angle. I don't think math will prohibit this idea. The fact that Hawking hasn't been awarded Nobel yet tells one that science hasn't validated his maths through observation yet. With present technology there is no way we can tell if hes right. Once it is found to be true, I am sure that those pseudo theories will disappear. Until then those theories will be given air by people who are not into all this. Science will be indistinguishable from any religion if it doesn't entertain contrasting views.Thanks

    The thing with mainstream science is that there is no such thing.
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    I am glad that you understand and appreciate Hawking's mathematics on black hole. Many people including me don't have a clue and it's implications on physical world appears bizarre.
    I would like to add that the implications of a black hole having any thermodynamic properties at all are far more wide-ranging than most people realise. For one thing it tells us that any 4-volume of space-time must have a finite number of microscopic degrees of freedom; also, it allows us to conjecture that the Einstein Field Equations may be viewed as equations of state of a globally thermodynamic system. Both of these are strong hints that, just like gravity can be regarded as an emergent geometric property of space-time in the presence of energy-momentum, the very notion of space-time itself may by an emergent phenomenon of something much more fundamental, with degrees of freedom other than those of Riemann geometry. The question is then of course - what is that "pre-geometry" ? This is where my own personal area of interest has been for a number of years now, and there are some interesting developments happening right now in theoretical physics.
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    In one of the science programs that I watched on TV, it was said that gravitons can seep into higher dimensions unlike photons. And the so called dark matter is really the matter that is present in those dimensions. But if that is so,we should be able to locate them using gravitation telescopes.
    Why?
    What does math say about properties of fundamental particles? Are these particles really fundamental? How do we know that anything is fundamental?
    If we turn to string theory and say that those strings are fundamental. Then again the question remains..why?they re vibrating only at those very particular frequencies, while they can vibrate in any which way they want. So can we call anything fundamental?
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    Administrator Markus Hanke's Avatar
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    Quote Originally Posted by MaxPayne View Post
    In one of the science programs that I watched on TV, it was said that gravitons can seep into higher dimensions unlike photons. And the so called dark matter is really the matter that is present in those dimensions. But if that is so,we should be able to locate them using gravitation telescopes.
    Why?
    This is an element of a model called "brane cosmology"; it is very interesting in its own right, but bear in mind that this is merely an idea, a hypothesis. There is no empirical indication ( let alone evidence ) that extra macroscopic dimensions actually exist.

    What does math say about properties of fundamental particles?
    The maths of the Standard Model concerns itself primarily with how the various particles behave and interact, rather than what they are on a fundamental level. We can reasonably accurately predict the outcome of most interactions involving the strong, weak, and electromagnetic forces, yet even here some unresolved questions remain ( e.g. asymptotic freedom of QCD etc etc ). The key tool here is quantum field theory in flat space-times, and their associated symmetries. We are only just starting to translate all of this into curved space-times, with interesting and surprising results, even at this early stage.

    How do we know that anything is fundamental?
    We can examine their properties theoretically, and test their behaviour in particle accelerators through deep inelastic scattering. There are obvious limits to both of these approaches, so at present we can never be quite sure if something is truly "fundamental".

    Are these particles really fundamental?
    Yes, that is one of the key questions, and one to which modern physics does not yet have a final answer. My personal take on things is - how meaningful is this question, really ? If we look at quantum field theories in curved space-times we will find that the entire notion of a "particle" is actually observer dependent - what one observers perceives to be a particle, is actually the vacuum ground state for another observer. This makes me wonder if particles are actually artefacts of a particular choice of coordinates on a topologically non-trivial space-time background, rather than fundamental entities in their own right. But that's just my take on things. A very, very interesting area of research !

    they re vibrating only at those very particular frequencies, while they can vibrate in any which way they want.
    They can't vibrate in any which way they want. There are constraints imposed by things like mathematical self-consistency and such, but you are right in saying that the number of possibilities is very large. In fact, it is somewhere in the region of 10^500 possible vacuum state configurations. Question is - which one, if any, is the right one that accurately describes our universe ? And is that choice arbitrary, or the result of something more fundamental ? These are all very interesting - and as per yet unanswered - questions.
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    Thanks!You are a treasure trove of knowledge/ Thanks to you, dictionary is closer to me than ever.
    The key tool here is quantum field theory in flat space-times, and their associated symmetries. We are only just starting to translate all of this into curved space-times, with interesting and surprising results, even at this early stage.
    Is it that difficult to translate quantum theory into curved space time? Almost a century have passed since Bohr(?) proposed his this theory. Why is it taking so long?
    Why is it still a work in progress? The whole thing is mathematical right?
    What are those results?
    10^500 possible vacuum state configurations. Question is - which one, if any, is the right one that accurately describes our universe ?
    10^500 Actual infinity doesn't exist, but this one comes close.
    How did we arrive at this particular number?
    So our Universe exists in just one of 10^500 configurations.(right?)
    And there could be 10^500 kinds of universe(s) out there.
    artifacts of a particular choice of coordinates on a topologically non-trivial space-time background
    I didn't get your point there.
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    Before I answer the below questions I should make it clear that quantum field theory and String theory are not my areas of expertise; I have not yet studied these in any considerable detail. Remember that I am not a scientist, just a self-studied amateur, and this is very advanced stuff - having said that I will still try my best to address your questions.

    Quote Originally Posted by MaxPayne View Post
    Is it that difficult to translate quantum theory into curved space time?
    It isn't quantum theory in general that is difficult to formulate in curved space-times ( that's actually fairly straightforward ), it is quantum field theory ( QFT ). They are not the same things.

    Why is it still a work in progress? The whole thing is mathematical right?
    Yes, the difficulties are overwhelmingly of a mathematical nature, but also conceptual. For example, the notion of locality when it comes to particles is difficult to define.

    What are those results?
    Some of the more important ones are :

    1. Particles can be created by time-dependent gravitational fields
    2. Particles also appear in time-independent fields were event horizons are present ( this is the origin of Hawking radiation, btw )
    3. The number of particles in a given volume of space is no longer well defined
    4. If a non-zero cosmological constant is present, the notion of "particle" in the context of QFTs ceases to make sense altogether, and can only be recovered in certain special cases
    5. The ground state of a field is observer dependent, i.e. what one observer sees as a particle may well be the vacuum state for another observer
    6. In conjunction with (5), the notion of "vacuum ground state" is no longer well defined canonically

    These are the consequences I am aware of, though I am sure there are others as well.

    How did we arrive at this particular number?
    Good question - I don't really know, to be honest. I would imagine that this is arrived at by imposing the condition of mathematical self-consistency on an otherwise generic String model.

    So our Universe exists in just one of 10^500 configurations.(right?)
    No, what I meant was that a String has that amount of different possibilities to vibrate in a self-consistent manner. In other words - there are 10^500 possible vacuum ground states, and we don't know how to tell which one correctly describes our universe, if any.

    I didn't get your point there.
    The point is simply that the entire notion of a "particle" isn't in any way fundamental at all, because it depends on the observer. As stated above, where one observer sees particles, another observer sees vacuum - this pretty much destroys any ideas of particles being fundamental and immutable.
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